ALBERT

Beschreibung: The objective of this work was to study the agronomic effects of the application of agri-food composts in almond trees (Prunus dulcis L.) cultivated in two different areas with different almond varieties (cv. Guara and cv. Ferraduel), with both in organic farming conditions throughout two cropping cycles. To reach this objective, almond production and quality issues (seed production, kernel yield, nutrient contents and kernel quality), as well as several physico-chemical and biological properties of the amended soils at the beginning and at the end of each campaign were studied. The four composts used (C1, C2, C3 and C4) were elaborated mainly using exhausted grape marc (EGM) and other wastes (waste from orange juice production, OW; waste from tomato soup production, TW; cattle manure, CM; and sheep manure, SM). Two treatments were used as control treatments, one based on sheep manure and another without any amendment. The composts used produced similar results in kernel yield and production compared to the traditional treatment (sheep manure). However, the thickness of the kernel was higher in the treatments using composts with exhausted grape marc and sheep manure or tomato soup waste. In relation to the almond quality, few differences related to the effect of treatments were observed, except for the content of proteins, sucrose, some fatty acids and vegetal sterols.

Beschreibung: Spinach is rich in minerals, vitamins, phytochemicals and bioactive compounds with health-beneficial effects; however, this plant also tends to accumulate oxalates and nitrates in their leaves. Apart from genotype, nutrition is the pre-harvest factor that mostly affects quality attributes at harvest. Particularly, the application of compost extracts (CE) may induce resistance against soil-borne diseases and favour secondary metabolism, increasing antioxidant capacity. The objective of this study was to evaluate the effects of different types of fertilization with or without the addition of CE, on harvest quality and shelf life of minimally processed spinach (Spinacia oleracea, var. Shrike RZ) stored during 12 days at 4 °C. A compost extract (CE) was prepared by mixing a compost from agri-food wastes (vine pruning, leek waste and olive mill waste) with deionized water. CE foliar applications were done from days 28 and 56 after sowing. The treatments applied were: Control; Control + CE; NPK (inorganic NPK fertilizer 15-15-15); NPK + CE; DMPP (ENTEC Nitrofoska® plus the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP)) and DMPP + CE. After harvest, spinach leaves were minimally processed and packaged to generate a passive modified atmosphere. Nitrate content in the control treatment was reduced by the addition of CE, although in the rest of the treatments, CE addition did not produce any effect. For nitrite contents, the lowest value was obtained for the Control + CE. Moreover, the oxalate content was the lowest for the control treatment with a decreasing trend throughout the storage. The treatment Control + CE also showed the highest initial total phenolic contents, with very similar values at the end of shelf life to those observed at harvest for all the treatments. The highest differences in color as regards the initial values were detected for DMPP. Microbial loads increased for all the treatments without differences between them. The atmosphere reached at the end of the cold storage was the same for all the cases, with CO2 and O2 around 10 kPa for each one of them. After 12 days at 4 °C, all the treatments were above the limit of usability, with the spinach leaves acceptable for consumption. The results found in this study indicate that the addition of CE might be convenient for obtaining spinach rich in bioactive compounds and with low concentrations of antinutritional factors, without affecting the microbial load of the final product.

Beschreibung: This work studies the changes in δ15N signature during the composting of sewage sludge (MS) and agri-food sludge (AS) with different bulking agents and the potential relationships between the changes in this parameter with both the source of the organic matter used as a raw material and the stability of the end-materials obtained. For this, eleven mixtures were prepared in commercial composting conditions using sewage sludge from municipal wastewater in a range of 60–85% (on a fresh weight basis) or agri-food sludge in a range of 65–75%, mixed with seven different pruning wastes as bulking agents. The thermal profile was monitored throughout the composting processes, and the main physico-chemical and chemical parameters were determined. The results obtained confirmed a correct development of the composting processes, observing slight differences in process evolution depending on the type of sludge used. The composts obtained showed adequate contents of nitrogen, phosphorus and potassium (NPK) and reached a good degree of maturity. Significant differences in the specific nitrogen isotopic composition were found in the initial materials. Moreover, the results suggest that the type of sludge had a main contribution in the δ15N value of the initial composting mixtures. The use of δ15N is recommended as an indicator of the composting process, especially to evaluate N dynamics, and the quality of the resultant compost.

Beschreibung: The organic wastes of plant origin and, in particular, those coming from sources related to tourism activities, such as those generated from golf courses and touristic coasts, constitute an increasing concern due to the rise in their production and their unsuitable management. Thus, this work aimed to assess the use of different composting strategies to manage these specific green wastes, such as grass clippings and pruning waste from a golf course and marine plant debris, mainly from posidonia (Posidonia oceanica L.). To this end, two composting scenarios were established: the first only considered green wastes in the composition of the composting mixtures, and the second used sewage sludge as a co-composting agent. The temperature of the piles was monitored, and physicochemical and chemical parameters were also studied throughout the process. The results obtained showed that composting is a feasible method to manage and recycle this type of green waste, obtaining end products with suitable physicochemical and chemical characteristics. However, proportions of sea plant wastes in the composting mixture higher than 30% can compromise the fertilizing value of the final compost. Moreover, the use of an additional co-composting agent (sewage sludge) improved the characteristics of the end products obtained, provided that this co-composting agent had suitable initial characteristics.